It is becoming more and more common for motor vehicles, particularly for private automobiles, to come equipped with passenger safety systems. These safety systems offer passengers protection from injury in case of collision or the like. Here, above all, the airbag system comes to mind. In these types of systems, instances of false tripping must be avoided at all costs, since very dangerous situations can result. When an airbag is released unintentionally, not only is the driver of the car robbed of his vision for a certain period of time, but he can also be startled--among other reasons because of the accompanying noise that is generated--, so that his ability to react is lost for a short time, or at the least is limited. Also, once an airbag has been released, it cannot be used again. It is a costly procedure to reinstall the system.
Two important criteria, which can lead to spurious tripping in the mentioned electronic restraint systems, are undefined hardware states during the time that a tripping sensor, for example, is brought in and out of circuit, as well as malfunctions or failures in a processing unit, whose task it is to trigger a final firing stage of the safety system. When the tripping sensor is brought in and out of circuit, the requisite supply voltage runs through the entire voltage range. As a result, states can arise in which, for example, the integrated circuits of the tripping sensor do not have any defined function, so that a spurious tripping can occur. The mentioned malfunctions or failures of the processing unit likewise lead to undefined states, so that the final firing state of the safety system can be triggered unintentionally.